I would be careful with that because, as I recall, Arizona has laws against "fornication" and "adultery" that do technically include polyamory. I seriously doubt they're enforced with any degree of eagerness but it's still a potential problem that you should keep in mind.
I'd talk to a lawyer first before signing any legal paperwork.
The bigamy laws in some states are written such that it can be considered bigamy if you "act as though you are married" with more than one person. I'm not 100% sure with Arizona which is why I recommend seeking legal advice.
I am as direct as a T-Rex with 'roid rage and about as subtle. It isn't intended to cause upset, I just prefer to talk plain. There are plenty of other people here who do the nice, polite thing much better than I can. I'm what you'd call a "problem dinner guest."